def sequence_search(seq, tgt):
    for i in range(len(seq)):
        if tgt == seq[i]:
            return "tgt数在seq中第{}个".format(i + 1)
    return None


if __name__ == '__main__':
    sequence = [99, 12, 33, 74, 521, 13, 14]
    target = 521
    print(sequence_search(sequence, target))
